Facility for Pulsed Extreme Ultraviolet Detector Calibration

Abstract

Extreme ultraviolet lithography, operating at a wavelength of about 13.5 nm, will require high‐repetition‐rate pulsed sources with average power outputs of over 100 W. As the output of the sources approaches this level, the low‐power, continuous‐wave calibrations of the detectors used to determine the source output will no longer be valid. The National Institute of Standards and Technology (NIST) is currently in the process of commissioning a system for the calibration of Extreme ultraviolet detectors under pulsed conditions similar to those produced by potential sources for extreme ultraviolet lithography. This system incorporates a laser‐produced plasma source based on a Kr droplet target. The plasma’s output is collimated by a grazing incidence parabolic reflector and split by a Mo/Si multilayer beamsplitter to provide two channels of illumination. Each channel is refocused onto filtered detectors to provide two signals that are proportional to the plasma Extreme Ultraviolet (EUV) output. Calibration i...